The invention relates to lighting fixtures and, more particularly, to indirect, direct, and direct/indirect lighting troffers that are well-suited for use with solid state lighting sources, such as light emitting diodes (LEDs).
Troffer-style fixtures are ubiquitous in residential, commercial, office and industrial spaces throughout the world. In many instances these troffer-style fixtures include troffers that house elongated fluorescent light bulbs that span the length of the troffer. Troffers may be mounted to or suspended from ceilings. Often the troffer may be recessed into the ceiling, with the back side of the troffer protruding into the plenum area above the ceiling. Elements of the troffer on the back side may dissipate heat generated by the light source into the plenum where air can be circulated to facilitate the cooling mechanism.
More recently, with the advent of efficient solid state lighting sources, these troffers have been used with LEDs. LEDs are solid state devices that convert electric energy to light and generally comprise one or more active regions of semiconductor material interposed between oppositely doped semiconductor layers. When a bias is applied across the doped layers, holes and electrons are injected into the active region where they recombine to generate light. Light is produced in the active region and emitted from surfaces of the LED.
LEDs have certain characteristics that make them desirable for many lighting applications that were previously the realm of incandescent or fluorescent lights. LEDs can emit the same luminous flux as incandescent and fluorescent lights using a fraction of the energy. In addition, LEDs can have a significantly longer operational lifetime.